The background is similar to Background of Invention, U.S. Pat. No. 5,074,608.
This invention is in the field of material handling, primarily related to cargo hooks. A previous U.S. Pat. No. 5,074,608 by Gabriel also describes a tongs-like cable-scooping device having some of the features of the present invention.
In the past, the operation of loading cargo has been a manual one, a hazard to personnel in such situations as loading an off-shore heaving, swaying ship. Ship personnel have had to manually place a ring attached to a cable onto a cargo hook, for cargo to be lifted by a hoist cable and placed elsewhere. In addition, remote unloading has been performed by applying a signal to a solenoid, as in the case of the Breeze-Eastern cargo hook. Should there be an open circuit between the switch and the solenoid, cargo would be incapable of remotely unloading. Should the application be to suspend cargo from a helicopter, a hazardous environmental condition could exist when manually loading cargo. Toxic waste sites also present a hazard for manually loading and unloading of cargo, such as drums. In other hazardous operations, ammunition and toxic chemicals may need to be transported to another site. It would be safer and less time-consuming not to use ground personnel and use the proposed hook instead.
Presently, Breeze-Eastern, Union, N.J., supplies the military with complex cargo hooks, capable of unloading cargo remotely with the application of a signal to a solenoid within the hook enclosure. Unfortunately, none of their cargo hooks can remotely snatch up a load cable. For remote releasing of cargo, the Breeze hook requires 22-28 VDC at 12 to 15 amperes, for release at dropping capacity for a typical 6000-lb. load, and a minimum release load of 7 lbs. for 15/8 inch travel of the rotatable hook portion, according to their specifications. In comparison,, the proposed cargo-hook requires 1 ampere at the same voltage to produce a jaws' closing force of 10 lbs.
If back-up load retention is not required, then voltage need not be applied to the hook for the electromagnet. The proposed permanent magnets can provide back-up positive load retention.